Since the deciphering of the human genome, the biological behavior of individual cells, such as the pathogenesis of cancer and the like, the mechanisms of embryogenesis/specialization of individual organs like the heart and cranial nerves, and so on, are being unraveled at the molecular level. Thus, when examining biological samples such as cells by using microscopes, there is a demand to observe the behavior at the level of individual biological molecules, such as proteins, DNA/RNA, and so forth. To achieve this, superresolution observation that exceeds optical resolution is becoming increasingly important.
In the related art, there is a known technique for obtaining an image with a resolution exceeding the diffraction limit (superresolution) by using a detector formed of a plurality of detector elements, such as a CCD or PMT array (for example, see Non Patent Literature 1). In the technique described in Non Patent Literature 1, a two-dimensional detector array is disposed at a position conjugate with the focal position of an objective lens, and a spot of return light coming from a laser beam spot scanned on a specimen by means of a scanner is subdivided and detected by the plurality of detector elements.
Then, a superresolution image of the specimen is created by arraying, in association with the scanning position of the scanner, pixel values obtained by summing light intensity signals of the return light coming from the same position on the specimen, which are detected by different detector elements at different detection timings in accordance with the laser beam scanning.